#!/usr/bin/env python
"""Script to manage releases.

* Create release branches
* Version bump setup.py, docs/conf.py, etc.
* Tag the releases
* Merge to master
* Push everything up to github.

The only thing this script doesn't do are the pypi uploads.
You'll need to do those yourself.


Usage::

    scripts/release 1.0.0

"""
import argparse
from subprocess import check_call, check_output

try:
    input = raw_input
except NameError:
    pass


def run(command):
    print("Running:", command)
    check_call(command, shell=True)

def verify_starting_state():
    must_be_on_develop_branch()
    no_outstanding_changes()

def must_be_on_develop_branch():
    output = check_output('git rev-parse --abbrev-ref HEAD',
                          shell=True).strip().decode('utf8')
    assert output == 'develop', 'Must be on the develop branch, not %r' % output

def no_outstanding_changes():
    output = check_output(
        'git status --short', shell=True).strip().decode('utf8')
    if output:
        raise AssertionError("Can't have any pending changes:\n%s" % output)


def create_release_branch(version):
    check_call('git checkout -b release-%s' % version, shell=True)


def bump_version(version):
    check_call('scripts/bumpversion %s' % version, shell=True)


# It might be nice to auto populate the merge/tag messages,
# right now it will pop up an editor.

def merge_to_master(version):
    run('git checkout master')
    run('git merge --no-ff release-%s' % version)


def tag_release(version):
    run('git tag -s -m "Tagging %s release" %s' % (version, version))


def merge_to_develop(version):
    run('git checkout develop')
    run('git merge --no-ff release-%s' % version)


def push_changes():
    run('git push origin develop')
    run('git push origin master')
    run('git push --tags')


def main():
    parser = argparse.ArgumentParser()
    parser.add_argument('release_version')
    args = parser.parse_args()

    verify_starting_state()
    create_release_branch(args.release_version)
    bump_version(args.release_version)
    merge_to_master(args.release_version)
    tag_release(args.release_version)
    merge_to_develop(args.release_version)
    push_changes()
    print('Completed, run "python setup.py sdist upload" to '
          "upload changes to pypi.")


if __name__ == '__main__':
    main()